Biocatalytic Hydrolysis of Soybean Protein Using Protease-Functionalized Magnetic Nanoparticles

The search for novel proteases with robust bioprocessing tendencies will benefit industrial production. Consequently, Aspergillus flavus KIGC protease was immobilised on iron oxide magnetic nanoparticles (IOMNPs) for the potential digestion of soybean protein. The protease was produced, partially purified, and used to functionalize the IOMNPs. Free and immobilized proteases were characterised and used to hydrolyze soybean protein. The results showed maximum protease production on day 7, with orange peel being the best carbon source. Characterization showed light scattering measurements of 72 and 81 nm for the IOMNPs and protease–IOMNP complex, respectively. The differential scanning calorimetry thermogram showed endothermic peaks at 193.97 °C and 150.93 °C for the IOMNPs and protease–IOMNP complex, respectively. The X-ray diffraction intensities differed between angles. Free and immobilized proteases showed optimal temperatures of 50 °C and 55 °C and pH values of 5.0 and 7.5, respectively. Km and Vmax were 0.002 mg/mL and 2 mg/min/mL for free protease and 0.0019 mg/mL and 3.85 mg/min/mL for immobilized protease, respectively. The immobilized protease showed 86.15% hydrolysis at 1.5 mg/mL of soybean protein after 18 h. The significant digestion of soybean protein by the IOMNP–protease compared to free protease points to the conjugate’s possible future applications pending further detailed study.